Silver halide emulsion sensitized with pentathiepane

ABSTRACT

A photosensitive silver halide photographic emulsion containing at least one compound selected from the group consisting of compounds having the formula   WHEREIN EACH OF R1, R2, and R3 and R4 is selected from the group consisting of a hydrogen atom, an alkyl group and an aralkyl group; and wherein R1 and R2, or R3 and R4 can combine to form a cycloalkyl group, is disclosed.

United States Patent Ushimaru et al.

[15] 3,656,955 [451 Apr. 18, W72

SILVER HALIDE EMULSION SENSITIZED WITH PENTATHIEPANE Inventors: Yoshuke Ushimaru; Yosuke Nakajima; Mitsunori Sugiyama; Fumihiko Nishio, Kanagawa; Shigeru Kobayashi, Osaka, all

of Japan Assignee: Fuji Photo Film Co., Ltd., Kanagawa,

Japan Filed: Aug. 28, 1970 Appl. No.: 68,041

Foreign Application Priority Data Aug. 28, 1969 Japan ..44/68219 US. Cl. ..96/107, 260/327 R Int. Cl

Field of Search ..96/ 107; 260/327 R [56] References Cited UNITED STATES PATENTS 3,503,758 3/ 1970 Wada et a1. ..260/327 R Primary Examiner-Norman G, Torchin Assistant Examiner-Won H. Louie, Jr. Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A photosensitive silver halide photographic emulsion containing at least one compound selected from the group consisting of compounds having the formula 9 Claims, No Drawings SILVER HALIDE EMULSION SENSITIZED WITH PENTATI-IIEPANE BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates to a silver halide photographic emulsion. More particularly, the present invention relates to a silver halide photographic emulsion which is chemically sensitized with a sulfur-containing compound.

2. Description of the Prior Art An object of the present invention is to increase the sensitivity of photosensitive silver halide photographic emulsions.

Various methods for increasing the sensitivity of photosensitive silver halide photographic emulsions during manufacture are known as a chemically sensitizing process. For example, compounds containing a labile sulfur (for example, sodium thiosulfate or thio-urea derivatives) are known as sulfur sensitizing agents. Also, a reducing agent, such as stannous chloride and hydrazine, is known as a reducing sensitizing agent. Some of these labile sulfur-containing compounds and reducing substances are considered to be contained in a natural gelatin for photography. Certain aurous or auric salts, for example aurous thiocyanate, have a chemically sensitizing action, and the method of utilizing this action is well known.

SUMMARY OF THE INVENTION The present inventors have found that a compound represented by the general formula DETAILED DESCRIPTION OF THE INVENTION The above compound is a useful sensitizing agent regardless of whether the emulsion is a silver chloride emulsion, a silver bromide emulsion, a silver iodide emulsion, or a mixed silver halide emulsion, or, further, whether the emulsion is a waterwashed or a water-unwashed emulsion.

Suitable chemical sensitizers having the above formula are However, the chemical sensitizers used in the present invention are not limited to these compounds.

The optimum amount of the sulfur sensitizer having the above described formula to be used is dependent on the specific compound selected, the type of silver halide, the particle size ripening temperature, the ripening time, and the pH and the pAg of the silver halide emulsion. However, the amount generally used is in the range of from 0.01 to mg per 1 mole of silver halide. However, where the sensitizer is used in combination with other sensitizers, the amount used can be smaller; Where the sensitizer is used in combination with any appropriate antifoggant, the amount can be larger.

The sulfur sensitizer used in the present invention can be used in combination with reducing sensitizers such as stannous chloride or thiourea dioxide, and also can be combined with auric or aurous salts, such as aurous thiocyanate, platinum salts, palladium salts, or sulfuncontaining compounds such as sodium thiosulfate, thiourea derivatives, and further can be used together with polyoxyalkylene compounds having a molecular weight of above 300 or onium compounds.

The sulfur-containing compound represented by the above described formula according to the present invention can be used not only in case of spectral sensitization but also without such sensitization. These can be usually applied to emulsions for black and white photography, for color photography, for X-ray, and for graphics.

The sulfur-containing compound represented by the above formula can be added to the photographic emulsion without any deleterious effects on stabilizers, antifoggants, hardeners, color developing agents, coating agents, and other emulsion additives.

The sulfur sensitizing agent represented by the above described formula is extremely useful for sensitizing a silver halide emulsion made of an inert gelatin and also can be used for sensitizing a silver halide emulsion in which at least one part of the protective colloid comprises other hydrophillic colloids such as a photographically labile gelatin or a polyvinylalcoho].

The sulfur sensitizing agent is particularly valuable in that the sensitizing efi'ect is markedly increased in combination with a thiosulfate ion, Le. a compound giving rise to a thiosulfate ion.

The synthesis of the compounds represented by the above formula is described in Tetrahedron Letters No. 6,576 (1966) for Compounds 1, Acta Chemica Scandinavia 13 1032 and 1715 1959) for Compound 2 and 4, respectively, and Fredge. A.Acta Chem. Scand. 12 891 (1958) for Compound 3.

The present invention is illustrated fiirther by reference to the following examples.

EXAMPLE 1 A highly sensitive neutral gelatino-silver bromo-iodide emulsion (5.0 percent silver iodide and 95.0 percent silver bromide) at the beginning of the chemical ripening was divided into five equal parts (Samples A to E). Samples C to E were mixed with Compound 1 in an alcohol solution and Sample B was mixed with a sensitizing natural gelatin, and were added with, as a metallic sensitizing agent, 7.5 mg of potassium chloroaurate (tetrahydrate) and 150 mg of potassium thiocyanate per 1 mole of silver halide in the form of an aqueous solution, and were chemically ripened under stirring at 50 C for 60 minutes. Further to 1 kg of each emulsion were added 30 mg of 3,3-diethyl-9-methylthiocarbocyamine bromide, 450 mg of chrome alum and mg of saponine and the mixture was coated on a cellulose triacetate base film and dried to obtain a photosensitive material of 14 microns in coating thickness. Next, the material so obtained was exposed stepwise to a light source of 5,400 1C for 1/50 second, developed with a developer having the following composition at 20 C for 10 minutes, fixed, washed with water, and, after drying, sensitometry was carried out. The results obtained are shown in Table 1.

Developer Composition N-Mehtyl-para-aminophenol Sulfate 2.0 g Sodium Sulfite (anhydrous) 100.0 g Hydroquinone 5.0 g Borax 2.0 g Water to 1000 ml TABLE 1 Added Sulfur amount, Relative Sample sensitizer mole/AgX sensitivity Gamma Fog A 100 0. 52 0. 04 B sensitizing 10.0 g 1,120 1.02 0.12

natural gelatin.

C Compound 1. 55 mg 1,100 1.04 0.07 D. Compound 2 60 mg 1, 240 1. 07 0. Compound 3. 65 mg 1.01 0.10

As can be seen from Table 1, a marked sensitizing effect was observed.

EXAMPLE 2 A neutral gelatino-silver bromochloride emulsion (58.0 mole percent silver bromide and 42.0 mole percent silver chloride) for a fine grained positive film at the beginning of chemical ripening was divided into three equal parts (Samples I F to H). Compound 2 in a methyl alcohol solution was added to Sample H and a sensitive natural gelatin was added to Sample G in the amount as shown in Table 2. Next, after ripening at 52 C for 3 minutes to 1 kg of each emulsion were added 300 mg of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene, 450 mg of chrome alum, and 120 mg of soponine, and the mixture was coated on a cellulose triacetate film base and dried to obtain a photosensitive material of 12 microns in coating thickness. The material so obtained was exposed stepwise to a light source of 2,660 K for l/20 second, developed with a developer having the following composition, fixed, washed with water and, after drying, sensitometry was conducted. The results obtained are shown in Table 2.

Developer Composition N-Methyl-para-aminophenol Sulfate 1.4 g lsomeric Potassium Bisulfite 8.0 g Hydroquinone 6.0 g Sodium Carbonate (mono hydrate) 22.5 g Citric Acid 0.7 g Potassium Bromide 0.9 g Water to 1000 ml As can be seen from the results in Table 2, a marked sensitizing effect was obtained.

A highly sensitive neutral gelatino-silver bromoiodide emulsion for an outer type reverse color film at the beginning of chemical ripening was divided into five equal parts (Samples I to M) and Compound 2 in a methyl alcohol solution was 7 added to each of samples K to M, and a sensitizing natural gelatin was added to Sample J in the amount as shown in Table 3. Next, to each of these five types of emulsions were added 7.5 mg of potassium chloroaurate tetrahydrate and 150 mg of potassium thiocyanate per 1 mole of silver halide in the form of an aqueous solution and was chemically ripened at 50 C under stirring for 70 minutes. Further, to 1 kg of the emulsion were added 30 g of 1,3-diethyl-5'-methoxy-6-methyl-seleno- Z-cyanineiodide, 450 mg of chrome alum and 120 mg of saponine, and the mixture was coated on a cellulose triacetate film base and dried to obtain a sensitive material of 8 micron in coating thickness. Next, the material so obtained was exposed stepwise to a light source of 5,400 K for l/20 second, developed using a developer having the following composition at 27 C for 3%minutes, fixed, washed with water and, after drying, sensitometry was carried out. The results obtained are shown in Table 3.

Developer Composition N-Methyl-para-aminophcnol Sulfate 1.0 g Sodium Sulfite (anhydrous) 60.0 g Hydroquinone 10.0 g Potassium Bromide 5.0 g Potassium Thiocyanate 1.5 g Potassium lodide (0.1%) 5.0 ml Sodium Hydroxide 2.0 g Water to 1000 ml TABLE 3 Added Sulfur amount, Relative Sample sensitizer mole/AgX sensitivity Gamma For:

I A 100 0. 49 O. 0!] J sensitizing 080 0. 84 0. 10

natural gelatin.

K Compound 2. 1,020 0. 87 0.10 L. 1,150 0.07 0.13 0. 0. 15

As can be seen from the results shown in Table 3, a marked sensitizing efiect was obtained.

EXAMPLE 4 A semi-ammonium process gelatino-silver bromoiodide emulsion (1.5 mole percent silver iodide and 98.5 mole percent silver bromide) at the beginning of chemical ripening was divided into three equal parts (Samples N to P) and to Sample 0 to P were respectively added compounds 1 and 2 in a methylalcohol solution in the amount shown in Table 4. Next, to Sample N were added 4.7 mg of sodium thiosulfate (pentahydrate) and 1.2 mg of sodium aurous thiosulfate (dihydrate) Na Au(S O .2l-l O in the form of an aqueous solution per 1 mole of silver halide. In the same manner, Sample O was added with 4.7 mg and 3.2 X10- mg of these salts per 1 mole of silver halide, respectively. Sample P was added with only 1.2 mg of sodium aurous thiosulfate (dihydrate) per 1 mole of silver halide.

Thereafter, these emulsions were chemically ripened at 50 C for 70 minutes.

These three types of emulsions were coated on a polyethylene terephthalate film base and dried to obtain a photosensitive material of 8 microns in coating thickness. Next, the materials so obtained were exposed through a continuous wedge to a light source of 5,400 K, and developed using a developer having the following composition at 20 C for 4 minutes.

Developer Composition N-Mehtyl-para-aminophenol Sulfate 4.0 g Sodium Sulfite (anhydrous) 60.0 g Hydroquinone 10.0 g Sodium carbonate (monohydrate) 53.0 g Sodium Bromide 3.0 g Water to 1000 ml After the samples were fixed, washed with water and dried, sensitometry was conducted to obtain the results shown in Table 4.

TABLE 4 Added Relaamount, tive Sulfur sensitizing mole/AgX sensi- Sample agent (mg) tivity Gamma Fog Na2S2O3-5H2O 4. 7. N. {l\Ia3Au(SQ03)2 2 1.2 100 1. 75 0.15

NazS2Oa-5H2O 4. 7 O h Na3Au(Sz03)2'H2O. 3 2X102 118 l. 85 0. 14

compousng 1) 1. 2 NaaA11( 2 3 221120." 1.2 P 2 u an 110 1. 35 0.15

in s s R4 wherein each of R R R and R is selected from the group consisting of a hydrogen atom, an alkyl group and an aralkyl group; and wherein R and R or R and R, can combine to form a cycloalkyl group.

2. The photographic emulsion as claimed in claim 1, wherein each of R R R and R is selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a benzyl group and a phenethyl group; and wherein R, and R or R and R, can combine to form a member selected from the group consisting of a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group.

3. The photographic emulsion as claimed in claim 1, wherein said compound is e mo CH2 s s s 4. The photographic emulsion as claimed in claim 1, wherein said compound is 5. The photographic emulsion as claimed in claim 1 wherein said compound is CHzOH CHz ss omomorn 011201120112 s s CHzCHzCH 6. The photographic emulsion as claimed in claim 1, wherein said compound is 7. The photographic emulsion as claimed in claim 1, wherein said emulsion contains additionally at least one compound having a thiosulfate ion.

8. The photographic emulsion as claimed in claim 7, wherein the thiosulfate compound is selected from the group consisting of sodium thiosulfate, sodium aurous thiosulfate and mixtures thereof.

9. A photosensitive element comprising a support having thereon at least a layer of the silver halide photographic emulsion as claimed in claim 1. 

2. The photographic emulsion as claimed in claim 1, wherein each of R1, R2, R3 and R4 is selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a benzyl group and a phenethyl group; and wherein R1 and R2 or R3 and R4 can combine to form a member selected from the group consisting of a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group.
 3. The photographic emulsion as claimed in claim 1, wherein said compound is
 4. The photographic emulsion as claimed in claim 1, wherein said compound is
 5. The photographic emulsion as claimed in claim 1, wherein said compound is
 6. The photographic emulsion as claimed in claim 1, wherein said compound is
 7. The photographic emulsion as claimed in claim 1, wherein said emulsion contains additionally at least one compound having a thiosulfate ion.
 8. The photographic emulsion as claimed in claim 7, wherein the thiosulfate compound is selected from the group consisting of sodium thiosulfate, sodium aurous thiosulfate and mixtures thereof.
 9. A photosensitive element comprising a support having thereon at least a layer of the silver halide photographic emulsion as claimed in claim
 1. 